importar js em html
<script type="text/javascript" src="yourfile.js"></script>
SteDeus
<script type="text/javascript" src="yourfile.js"></script><script type="text/javascript" src="external.js"></script><script src="script.js" defer></script>
<!--just add defer attribute so script will execute at last--><html>
<head>
<meta charset="utf-8">
<title>Softhunt.net</title>
</head>
<body>
<form>
<a href="#" onclick="display()">Click Me</a>/>
</form>
<script src="index.js">
</script>
</body>
</html>